Pumps



Nov. 15, 1966 J. GUTKOWSKI 3,285,192

I PUMPS Filed Oct. 29, 1964 a Sheets-Sheet 1 INVENTOE ATTOENEV5 Nov. 15, 1966 J. GUTKOWSKI 3,285,192

PUMPS Filed Oct. 29, 1964 5 Sheets-Sheet 2 INVENTCIE Jpwusz G-wrKowsKi ATTORNEYS Nov. 15, 1966 J. GUTKOWSKL PUMPS 5 Sheets-Sheet 3 Filed Oct. 29, 1964 INVENTOE dmvusz wrxowsxi United States Patent 3,285,192 PUMPS Janusz Gutkowski, 7 Rufus Close, Lewes, England Filed Oct. 29, 1964, Ser. No. 407,359 Claims priority, application Great Britain, Oct. 30, 1963, 42,77 7 63 23 Claims. (Cl. 103-457) The invention relates to pumps and more particularly relates to forms of pump which may be used with either compressible or incompressible fluids.

An object of the invention is to provide a new and improved pump.

According to one aspect, the invention consists in a pump having a pressure enclosure defined by a cylindrical wall and two end faces which are both generally inclined to the axis of the cylinder, wherein the two end faces are carried on two different members which are relatively rotatable and resiliently urged into mutual contact at said inclined faces, and wherein an inlet port and an outlet port are provided which are opened and closed by said relative rotation.

According to another aspect, the invention consists in a pump including a cylinder closed at one end by a surface which is generally inclined at an acute angle to the axis of the cylinder; a piston adapted to be a sliding and rotating fit within the cylinder, the crown of which piston is inclined at an angle corresponding to that of the closed end of the cylinder; means to cause simultaneous relative rotational and sliding motion of the piston and cylinder with the piston crown in continuous engagement with the cylinder end surface and an inlet port and an outlet port communicating with the cylinder and arranged to be opened and closed by said relative motion.

According to another aspect, the invention consists in a pump including a cylinder with a first piston adapted to be a sliding fit therein and a second piston adapted to be a rotating fit therein, wherein the crowns of both pistons are generally inclined at corresponding acute angles to the axis of the cylinder, wherein guide means are provided to constrain the first piston against rotation in the cylinder and resilient means are provided to urge the first piston into contact with the second piston and wherein rotation of the second piston causes reciprocation of the first piston and causes inlet and outlet ports communicating with the cylinder to be opened and closed cyclically.

Preferably the end faces of said members, or the end face of said cylinder or the crown or crowns of the piston or pistons as the case may be, have an outer portion which is in the form of a cam surface generated by a radius of the cylinder moving round each of the end faces of the member or the end face of the cylinder or the piston crown as the case may be.

There follows a description by way of example of a method of performing the invention with reference to the accompanying drawings in which:

FIGURE 1 is a longitudinal section of a simple form of pump in accordance with the invention;

FIGURE 2 is a longitudinal section on the line IIII of FIGURE 1;

FIGURE 3 is a longitudinal section through an alternative form of pump in accordance with the invention;

FIGURE 4 is a section on the line IV-IV of FIG- URE 3;

FIGURE 5 is a longitudinal section through a further alternative form of pump in accordance with the invention;

FIGURE 6 is a section on the line VIVI of FIG- URE 5;

FIGURE 7 is a section through another pump in accordance with the invention and through a squirrel cage electric motor employed to drive the pump;

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FIGURE 8 is a section through part of the central shaft of the pump of FIGURE 7 illustrating the porting arrangement;

FIGURE 9 is a side view of an alternative form of piston which may be used in any of the embodiments of FIG- URES 1 to 6;

FIGURE 10 is a view from the front and slightly from above of the piston illustrated in FIGURE 9;

FIGURE 11 is a plan view of the piston of FIGURE 9;

FIGURE 12 is a section through a piston similar to that of FIGURES 9 to 11 but adapted to the embodiment of FIGURES 7 and 8; and

FIGURE 13 is a side view of a further modification of the piston of FIGURES 9 to 11.

The pump illustrated in FIGURE 1 has a cylindrical casing 11 with a circular bore 12 which forms a wall of the pressure enclosure of the pump. The inner end wall 13 of the cylinder is inclined to the axis of the cylinder. A piston 14, which may, for example, be made from a synthetic material such as nylon or polypropylene, has an inclined crown, the inclination of which corresponds to the inclination of the end wall 13 of the cylinder. A resilient means such as a spring 15 urges the piston 14 into contact with the inner face 13 of the cylinder. The end of the spring remote from the piston is held in a bush 16 which is mounted on the end of a drive shaft 17 of an electric motor 19. The spring 15 is a tight fit in a circular recess 18 in the piston and in the bush 16. Thus, any rotation imparted to the shaft 17 is applied through the spring 15 to the piston 14.

An inlet port 23 and an outlet port 24 are provided in the side wall of the cylinder near the inner end thereof. In this example the inlet port and the outlet port are at diametrally opposite positions.

In operation the shaft 17 is rotated and the piston 14 rotates with the shaft. Throughout this rotation some part of the crown of the piston continues to bear against the end wall 13 of the cylinder. It can easily be seen that when half a rotation has been completed, from the position shown the piston crown will lie up against the end wall 13 leaving no space within the pressure enclosure of the cylinder. At intermediate positions between the position shown in FIGURES 1 and 2 and the position described in the preceding sentence, the volume in the cylinder progressively decreases. In the following half revolution the volume within the cylinder increases progressively from zero until the maximum volume is again reached at the position shown in FIGURES 1 and 2.

During this cycle the inlet and outlet ports 23 and 24 are closed and opened by the piston. In the position shown both inlet and outlet ports are open. However, after a small part of a revolution from the position shown (in this example just under quarter of a revolution) the inlet port is closed by the piston, the outlet port remaining open. The volume in the cylinder thus decreases only slightly from the maximum value before the inlet port is closed. With further rotation of the piston the volume in the cylinder continues to decrease and fluid in the cylinder is expelled through the outlet port. This pumping action continues until the outlet port is closed by the piston after about half a revolution from the position shown. Shortly after this, with further rotation of the piston, the inlet port is again opened. Further rotation continuously increases the volume within the cylinder and causes fluid to be drawn into the cylinder from the inlet port. Fluid continues to be drawn in until the position illustrated in FIGURES 1 and 2 is again reached. With continuous rotation of the shaft 17 the cycle of drawing fluid in from the inlet port and expelling it through the outlet port is repeated continuously.

If the pressure at the outlet port of the pump exceeds a predetermined value, which may for example occur if there is a blockage in an outlet pipe, the pressure force on the piston when the outlet port is open exceeds the force exerted on the piston by the spring and thus causes the piston to be moved away from the end wall 13 of the cylinder. As a result of this, no further fluid is forced out from the outlet port. Thus, it can be seen that the pump is self-relieving.

Under normal operation conditions the rating of the spring must be such that the force exerted by the spring is at least equal to the sum of the fluid pressure force on the piston and inertia forces resulting from acceleration and deceleration of the piston.

With the porting arrangements illustrated in the embodiment of FIGURES 1 and 2 there is a short time during each revolution of the pump (i.e. at the position illustrated) at which both inlet and outlet ports are open.

For this reason it is convenient to arrange the ports and placed by a piston 31 which is spring loaded by means of i a spring 32 to bear against a further piston 33 which is rotatable by means of a shaft 34. In this arrangement the piston 33 is not spring loaded but instead bears against an end wall 35 of the pump casing 36. Piston 33 is formed with a shaft 34 which is rotatably mounted in the end wall 35 of the pump casing. Piston 31 is slotted ,at 37 and is constrained against rotation in the cylinder 'by means of a pin 38 which extends at both ends into casing 36.

In operation, when the shaft 34 is rotated, piston 33 rotates ,with this shaft and piston 31 is caused to reciprocate as it is held in contact with the crown of piston 33 by the spring 32. Rotation of piston 33 causes inlet and outlet ports 39 and 41 to be opened and closed cyclically. In this embodiment the inlet port closes before the outlet port opens and thus there is no problem of back-flow. However, if the problem of back-flow can be met in some other way, both ports may, if desired, be moved slightly towards the reciprocatory piston 31. The volume of the cylinder increases and decreases as in the arrangement of FIGURES 1 and 2 and thus a pumping action is established. The pump of FIGURE 3 is selfrelieving in a similar way as in the arrangement of FIG- -URES 1 and 2.

FIGURES 5 and 6 illustrate a pump which is similar to that of FIGURE 4. The only difference is that a fluid line is connected from the outlet port of the cylinder to a chamber 42 formed in the cylinder behind piston 31. The outlet line 43 from the pump as a whole leads out from this space 42.

The effect of this connection is that the outlet pressure of the pump is always applied behind the piston 31. Thus, when the pressure in the cylinder is equal to the pressure behind the piston 31 (i.e. the outlet port 41 of the cylinder is open) there is no longitudinal fluid pressure force acting on piston 31. At all other times the pressure behind the piston 31 is greater than the pressure in front of the piston. Thus, in the embodiment of FIGURE 5, the spring 32 is necessary only to overcome inertia and friction forces caused by reciprocation of piston 31.

FIGURES 7 and 8 illustrate a substantially diiferent form of the invention. The pump illustrated in FIG- URES 7 and 8 has a cylindrical casing 51 with a circular bore 52 which forms a wall of the pressure enclosure of the pump. The inner end Wall 53 of the cylinder is in- .a squirrel cage electric motor.

clined to the axis of the cylinder. A piston 54 has an inclined crown, the inclination of which corresponds to the inclination of the end wall 53 of the cylinder. The end face of the cylindrical casing 51 has an axial circular aperture which carries a shaft 56. The cylindrical casing 51 is freely rotatable on shaft 56. The other end of casing 51 is supported by a ball race 57.

Piston 54 also has a central aperture through which shaft 56 extends. A resilient means such as a helical coil spring 55 bears against a collar 62 mounted on shaft 56 and the piston 54 and urges the piston into contact with the end face '53 of the cylinder. The spring prevents relative rotation between the shaft and the piston, while permitting relative sliding movement. The casing 51 and shaft 56 should be constrained against relative axial movement. In this example this constraint is provided in conjunction with a squirrel cage electric motor as will be described hereinafter.

In this embodiment inlet and outlet ports are provided in the central shaft; the arrangement of these ports can best be seen from FIGURE 8. The shaft is drilled centrally from one end at 63 and this drilling communicates with an inclined drilling 64 which forms the inlet port;

similarly, the shaft is centrally drilled at 65 from the opposite end and this central drilling communicates with an inclined drilling 66 which forms the outlet port. Thus, in this arrangement the inlet and outlet fluid connection lines are coaxial with the pump.

As illustrated diagrammatically in FIGURE 7, this pump may be mounted coaxially within the rotor 67 or The stator 68 of this motor is carried on the central shaft 56. It should be pointed out that the squirrel cage motor 67, 68 is simply one convenient form of driving motor for this pump. One advantage of this arrangement is that it enables a very compact motor-and-pump unit to be produced.

A pump of this kind is particularly suitable for hydraulics applications and thus the fluid may be what is generally known as hydraulic fluid, i.e. fluid of the type generally used in hydraulic systems. In order to avoid providing effective seals between the shaft 56 and the casing 51, between the shaft 51 and piston 54, and between piston 54 and casing 51 it may be expedient to operate the motor in the same fluid as that which the pump is pumping. For this reason a fluid connection 58 is shown between the interior of the motor and the low pressure side of the pump. In this way the motor remains full of fluid at the inlet pressure of the pump; any seepage of high pressure fluid into the motor results in fluid flow through the connection 58 to relieve pressure build up in the motor.

The operation of the pump illustrated in FIGURES 7 and 8 is very similar to the operation of the pumps already described above. In this embodiment it is the cylindrical casing 51 which rotates while the piston 56, which is mounted on the stationary shaft 56, is prevented from rotating. However, the operation of the pump can most easily be understood by imagining the casing to be stationary, the piston and shaft to be rotating and the piston to be reciprocating within the casing. Looked at from this point of view, the only significant difference between the arrangement of FIGURE 7 and that of FIGURE 1, is that in FIGURE 7 the ports are arranged in a central shaft 65 whereas in the arrangement of FIGURE 1 the ports are arranged in the wall of the cylinder.

It should be realised that although in describing operation of the pumps described above it has been indicated that either the piston or the cylinder is prevented from rotating whilst the other of these two components rotates, it is equally possible to constrain the part which has been described as rotating against rotation and to rotate the part which has been described as non-rotating. In the embodiments of FIGURES 1 to 6 some modification of the simple case these ports would be rotating.

In the piston illustrated in the embodiments described above there is only point contact between the two pistons or the piston and the end wall of the casing as the case may be. While such an arrangement may be satisfactory with small bearing loads between the two members concerned, for high speed and high pressure operation it is convenient to provide substantial areas of contact between the two members to prevent excessive wear.

FIGURES 9, l and 11 illustrate a piston which has a crown which is shaped to give effective area contact when employed with another piston or a cylinder end wall of the same configuration. The outer portion 71 of the piston crown forms a cam surface which, in operation of the pump, mates with a corresponding surface on a similarly shaped member. It can be seen that the cam surface is in the form of a surface generated by a radius of the cylinder moving round the edge of the piston crown. For the embodiments of FIGURES 1 to 6 the configuration of the central part of the piston crown is not critical. In FIGURES 9, and 11, this inner portion of the crown is shown to be a plane circle 72 perpendicular to the axis of the cylinder; in both the members which are to be interengaged, i.e. either two pistons or one piston and a cylinder end wall, these plane circles are arranged midway between the highest and lowest point of the cam surface. This ensures that in one rotational position the two members close together leaving zero volume between them.

In the embodiment of FIGURES 7 and 8, the same form of cam surface as described with reference to FIG- URES 9 to 11 can be employed. However, in order to effectively open and close the ports 64 and 66 in the central shaft 56 of FIGURE 7, it is desirable that the inner portion of the piston, and also that of the cylinder end face, should be inclined to the axis of the cylinder at an acute angle. A section of such a piston is illustrated in FIGURE 12. The cam surface 75 corresponds to the cam surface 71 of FIGURES 9 to 11. However, the plane circular face 72 of FIGURES 9 to 11 is replaced in FIGURE 12 by a plane inclined surface 76.

FIGURE 13 is a side view of a further alternative form of piston which may be employed in the embodiments of FIGURES 1 to 6. In FIGURE 13 the outer edge of the piston crown, as seen in side elevation in FIGURE 13, takes on a curved form instead of the straight inclined form shown in FIGURE 11. The other piston or the cylinder end wall which mates with the piston 13 should also take the same form as this piston. The reason for introducing such a curvature is to modify the longitudinal acceleration characteristics of the piston in order to enable a lower rating spring to be used and/ or to prevent excessive wear on the cam surface at the localities which are in mutual contact when accelerations are very high. A suitable form of curve to prevent a high acceleration peak can easily be designed by those skilled in the art of cam design.

As a guide to the design of such a curve it should be stated that in the rotational position at 180 to that shown in FIGURES 1 to 6, the inner and outer extremities of the cam surfaces should be in mutual contact while at intermediate positions on the cam surfaces there should be a small gap. A detailed study of FIGURE 13 shows that at point A the cam surface is nearer the lower than the upper extremity (in the configuration of the drawing) of the cam surface.

The angle of inclination of the piston crowns and the end surface of the cylinder is a matter of choice. In FIGURES 1 to 8 this angle is shown as 60. If this angle is increased beyond 60, the stroke and thus the volume delivered per revolution of the pump is decreased.

In some pumps the volume of the pressure chamber, i.e., the volume within the cylinder, changes while the ports leading into the pressure chamber are closed. Such pumps can normally be used only with compressible fluids. In the embodiment of FIGURES 1 and 2, this situation occurs when the outlet port closes just before the pump reaches a configuration which is from the position illustrated in the figures. At this stage the small volume of fluid is trapped in the pressure chamber. If the two relatively moving members e.g. the piston and cylinder in FIGURE 1, were constrained in such a way as to always maintain the two inclined surfaces in mutual contact, in the presence of an incompressible fluid the pump would be unable to continue to rotate as soon as the outlet port is closed. However, because the two members are maintained in contact only by spring pressure, What happens in practice is that the two members are forced slightly apart against the spring for this part of the revolution. Thus, it can be seen that pumps in accordance with the invention are suitable for both compressible and incompressible fluids.

It should be mentioned that the inlet and outlet ports need not necessarily be diametrically opposed within the cylinder; it may prove advantageous to rotate either or both of the ports around the cylinder from the positions shown or to move one or both of them axially from the position shOWn. It may also prove expedient to employ shapes other than the circular ports shown.

What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. A pump including:

(a) a cylinder closed at one end by a face which is generally inclined at an acute angle to the axis of the cylinder;

(b) a piston within the cylinder adapted to be a sliding and rotating fit therein;

(c) a piston crown on the piston generally inclined at an angle corresponding to the inclination of said face;

(d) resilient drive means operatively connected to the piston for urging the piston orown into contact with said face and for rotating the piston relatively to the cylinder; and

(e) an inlet port and an outlet port communicating with the interior of the cylinder through the walls thereof and arranged to be opened and closed by rotational and translational movement of the piston within the cylinder.

2. A pump according to claim 1, wherein the resilient drive means is a helical coil spring.

3. A pump according to claim 1, wherein the piston crown has an outer portion which is in the form of a cam surface generated by a radius of the cylinder moving ,round the edge of the piston crown.

4. A pump according to claim 3, wherein that part of the piston crown within said outer cam surface portion is in the form of a plane circle perpendicular to the axis of the cylinder.

5. A pump according to claim 3, wherein the cam surface at the outer edge of the piston deviates from the form of the line of intersection of an inclined plane with the cylinder wall.

6. A pump according to claim 1, wherein the outlet port is so positioned in relation to the inclined face of the cylinder that it is closed by the piston before the rotational position is reached at which the volume within the cylinder is a minimum.

7. A pump including:

(a) a cylinder;

(b) a first piston within the cylinder adapted to be a sliding fit therein;

(c) a first piston crown of the first piston generally inclined at an acute angle to the axis of the cylinder;

(d) guide means for constraining the first piston against rotation in the cylinder;

(e) a second piston within the cylinder adapted to be a rotating fit therein;

(f) a second piston crown of the second piston generally inclined at an angle corresponding to the inclination of the first piston crown and facing said first piston crown;

(g) thrust means for restraining said second piston against axial motion;

(h) drive means operatively connected to the second piston for rotating the second piston relatively to the cylinder;

(i) resilient means operatively connected to the first piston to urge the crown thereof into contact with the second piston crown;

(j) an inlet port and an outlet port communicating with the interior of the cylinder through the walls thereof and arranged to be opened and closed by rotational movement of the second piston within the cylinder.

8. A pump according to claim 7, wherein the resilient means is a helical coil spring.

9. A pump according to claim 7, wherein the piston crowns have outer portions which are each in the form of a cam' surface generated by a radius of the cylinder moving round the edge of the respective piston crown.

10. A pump according to claim 9, wherein that part of each piston crown within said outer cam surface portion is in the form of a plane circle perpendicular to the axis of the cylinder.

11. A pu-rnp according to claim 9, wherein the cam surface at the outer edge of the piston deviates from the form of the line of intersection of an inclined plane with the cylinder wall.

12. A pump according to claim 7, wherein the outlet port is so positioned in relation to the inclined face of the cylinder that it is closed by the second piston before the rotational position is reachedat which the volume within the cylinder is a minimum.

13. A pump according to claim 7 including:

(a) a chamber behind said first piston defined by the piston and side and end walls of the cylinder; and

(b) a fluid connection from the outlet port of the pump to said chamber behind said first piston.

14. A pump according to claim 13 including an outlet line from the pump as a Whole connected to said chamber behind said first piston.

15. A pump according to claim 13, wherein the piston crowns have outer portions which are each in the form of a cam surface generated by a radius of the cylinder moving round the edge of the respective piston crown.

16. A pump according to claim 15, wherein that part of each piston crown within said outer cam surface portion is in the form of a plane circle perpendicular to the axis of the cylinder.

17. A pump according to claim 15, wherein the cam surface at the outer edge of the piston deviates from the form of the line of intersection of an inclined plane with the cylinder wall.

18. A pump including:

(a) a cylinder having an end face which is generally inclined at an acute angle to the axis of the cylinder;

(b) a piston within the cylinder adapted to be a sliding and rotating fit therein;

(c) a piston crown on the piston gener-allyinclined at an angle corresponding to the inclination of said face;

(d) drive means operatively connected to the cylinder for rotating it relatively to the piston;

(e) resilient means operatively connected to said piston for urging it into contact with said end face;

(f) a central shaft extending through apertures in said cylinder end face and in said piston;

(g) constraint means for preventing relative rotational movement between said piston and said central shaft; and

'(h) an inlet port and an outlet port communicating with the interior of the cylinder through the central shaft and arranged to be opened and closed by relative rotational and translational movement between the piston and the cylinder.

19. A pump according to claim 18, wherein the resilient means is a helical coil spring.

20. A pump according to claim 18, wherein the piston crown has an outer portion which is in the form of a cam surface generated by a [radius of the cylinder moving round the edge of the piston crown.

21. A pump according to claim 20, wherein the cam surface at the outer edge of the piston deviates from the form of the line of intersection of an inclined plane with the cylinder wall.

22. A pump according to claim 18, wherein the outlet port is so positioned in relation to the inclined face o f the cylinder that it is closed by the piston before the rotational position is reached at which the volume within the cylinder is a minimum.

23. In combination, a pump according to claim 18 and a squirrel ca'ge electric motor, the pump being situated within the rotor of the squirrel cage motor.

References Cited by the Examiner UNITED STATES PATENTS 1,404,625 1/ 1922 Marquet 103-157 3,136,255 6/1964 Plato 1031'57 FOREIGN PATENTS 166,141 11/1955 Australia. 690,836 6/1936 France. 1,351,516 12/1962 France.

MARTIN P. SCI-IWADRON, Primary Examiner.

HENRY F. RADU-AZO, Examiner. 

1. A PUMP INCLUDING: (A) A CYLINDER CLOSED AT ONE END BY A FACE WHICH IS GENERALLY INCLINED AT AN ACUTE ANGLE TO THE AXIS OF THE CYLINDER; (B) A PISTON WITHIN THE CYLINDER ADAPTED TO BE A SLIDING AND ROTATING FIT THEREIN; (C) A PISTON CROWN ON THE PISTON GENERALLY INCLINED AT AN ANGLE CORRESPONDING TO THE INCLINATION OF SAID FACE; (D) RESILIENT DRIVE MEANS OPERATIVELY CONNECTED TO THE PISTON FOR URGING THE PISTON CROWN INTO CONTACT WITH SAID FACE AND FOR ROTATING THE PISTON RELATIVE TO THE CYLINDER; AND (E) AN INLET PORT AND AN OUTLET PORT COMMUNICATING WITH THE INTERIOR OF THE CYLINDER THROUGH THE WALLS THEREOF AND ARRANGED TO BE OPENED AND CLOSED BY ROTATIONAL AND TRANSLATIONAL MOVEMENT OF THE PISTON WIHTIN THE CYLINDER. 